248 On the Fermentation and 
gummy mucilages, barley, &c. pass by a sort of fer- 
mentation into saccharine matter; but of this I shall 
speak more at large when treating on the subject 
of malting. 
No other but saccharine matter is susceptible of 
fermentation, and it is necessary to observe a pro- 
per proportion betwixt the density of the liquor and 
the quantity of yest; for, although artificial fer- 
ment is not absolutely necessary to produce fermen- 
tation, yet it has a tendency (as is well known) to 
accelerate its progress. 
The heat of the liquor must also be regulated ac- 
cording to the density, as a greater or smaller de- 
gree of heat is excited during fermentation, accord- 
ing to the quantity of fermentible matter which it 
contains. | 
The phenomena which accompany fermentation, 
together with many other interesting particulars, may 
be found in an ingenious essay inserted in the second 
volume of the Memoirs of this society.* I shall, 
therefore, proceed to a description of the instru- 
ment by which I regulated the gravity of my worts. 
The scale of my saccharometer corresponds to 
that of Blake’s, but the form is materially different. 
It is so constructed, that a plate above the ball is 
sufficiently large to containa scale of the intermediate 
* Experiments and Observations on Ferments and Fer- 
mentation, by T. Henry, F.R.S. 
